Okruschite
A valid IMA mineral species
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About Okruschite
Martin Okrusch
Formula:
Ca2Mn2+5Be4(AsO4)6(OH)4 · 6H2O
Colour:
White
Lustre:
Vitreous
Specific Gravity:
3.33
Crystal System:
Monoclinic
Member of:
Name:
Named after Professor Martin Okrusch (3 December 1934 in Guben - ), University of Wuerzburg, Würzburg, Germany.
Unique Identifiers
Mindat ID:
46010
Long-form identifier:
mindat:1:1:46010:1
IMA Classification of Okruschite
Classification of Okruschite
8.DA.10
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
A : With small (and occasionally larger) cations
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
A : With small (and occasionally larger) cations
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Okr | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Okruschite
Vitreous
Transparency:
Transparent
Colour:
White
Comment:
Semitransparent
Streak:
White
Cleavage:
Distinct/Good
Distinct on (010).
Distinct on (010).
Parting:
Parting on (100).
Density:
3.33(2) g/cm3 (Measured) 3.340 g/cm3 (Calculated)
Optical Data of Okruschite
Type:
Biaxial (-)
RI values:
nα = 1.671(3) nβ = 1.682(2) nγ = 1.687(3)
2V:
Measured: 65° (5)
Max. Birefringence:
δ = 0.016
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
Dispersion Weak, r > v.
Optical Extinction:
X = b.
Chemistry of Okruschite
Mindat Formula:
Ca2Mn2+5Be4(AsO4)6(OH)4 · 6H2O
Element Weights:
Crystallography of Okruschite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 16.33(4) Å, b = 12.03(3) Å, c = 6.93(1) Å
β = 94.84(5)°
β = 94.84(5)°
Ratio:
a:b:c = 1.357 : 1 : 0.576
Unit Cell V:
1357 ų
Z:
2
Morphology:
Blocky, thick-tabular crystals consisting of curved and differently oriented laths. Forms include {010} (major), {100}, {001}, and probably {110}.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.68 Å | (39) |
| 4.95 Å | (34) |
| 4.17 Å | (34) |
| 3.25 Å | (100) |
| 3.11 Å | (32) |
| 2.841 Å | (27) |
| 2.711 Å | (26) |
| 1.726 Å | (26) |
Locality:
Comments:
Fuchs Quarry, Bavaria, Germany. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Okruschite
General Appearance of Type Material:
Tabular aggregates up to 0.15 × 0.3 × 0.3 mm in size of curved and somewhat misaligned laths.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4434/1
Geological Setting of Type Material:
In a hydrothermal vein cross-cutting rhyolite.
Associated Minerals at Type Locality:
Synonyms of Okruschite
Other Language Names for Okruschite
Dutch:Okruschiet
German:Okruschit
Relationship of Okruschite to other Species
Member of:
Other Members of Roscherite Group:
| Atencioite | Ca2Fe2+3Mg2Be4(PO4)6(OH)4 · 6H2O | Tric. 1 : P1 |
| Footemineite | Ca2Mn2+Mn2+2Mn2+2Be4(PO4)6(OH)4 · 6H2O | Tric. 1 : P1 |
| Greifensteinite | Ca2Fe2+5Be4(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/b |
| Guimarãesite | Ca2Be4Zn5(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/b |
| Roscherite | Ca2Mn2+5Be4(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/m |
| Ruifrancoite | Ca2(◻,Mn)2(Fe3+,Mn,Mg)4Be4(PO4)6(OH)4(OH,H2O)2 · 4H2O | Mon. 2/m : B2/b |
| Zanazziite | Ca2Mg5Be4(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/b |
Common Associates
Associations Based on Photo Data:
| 2 photos of Okruschite associated with Arseniosiderite | Ca2Fe3+3(AsO4)3O2 · 3H2O |
| 1 photo of Okruschite associated with Calcite | CaCO3 |
Related Minerals - Strunz-mindat Grouping
| 8.DA.05 | Bearsite | Be2(AsO4)(OH) · 4H2O |
| 8.DA.05 | Moraesite | Be2(PO4)(OH) · 4H2O |
| 8.DA.10 | Zanazziite | Ca2Mg5Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Atencioite | Ca2Fe2+3Mg2Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Guimarãesite | Ca2Be4Zn5(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Footemineite | Ca2Mn2+Mn2+2Mn2+2Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Greifensteinite | Ca2Fe2+5Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Roscherite | Ca2Mn2+5Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Ruifrancoite | Ca2(◻,Mn)2(Fe3+,Mn,Mg)4Be4(PO4)6(OH)4(OH,H2O)2 · 4H2O |
| 8.DA.15 | Uralolite | Ca2Be4(PO4)3(OH)3 · 5H2O |
| 8.DA.20 | Weinebeneite | CaBe3(PO4)2(OH)2 · 4H2O |
| 8.DA.25 | Tiptopite | K2(Na,Ca)2Li3Be6(PO4)6(OH)2 · H2O |
| 8.DA.40 | Spencerite | Zn4(PO4)2(OH)2 · 3H2O |
| 8.DA.45 | Glucine | CaBe4(PO4)2(OH)4 · 0.5H2O |
Other Information
IR Spectrum:
The IR spectrum is unique and considered a diagnostic tool.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Okruschite
mindat.org URL:
https://www.mindat.org/min-46010.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Okruschite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No 18. Mineralogical Magazine, 77 (8) 3249-3258 doi:10.1180/minmag.2013.077.8.15
Chukanov, Nikita V., Möhn, Gerhard, Pekov, Igor V., Belakovskiy, Dmitriy I., Bychkova, Yana V., Gurzhiy, Vladislav V., Lorenz, Joachim A. (2014) Okruschite, Ca2Mn2+5Be4(AsO4)6(OH)4·6H2O, a new roscherite-group mineral from Sailauf, Bavaria, Germany. European Journal of Mineralogy, 26 (4) 589-595 doi:10.1127/0935-1221/2014/0026-2387
Localities for Okruschite
Showing 1 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Germany (TL) | |
| Williams et al. (2013) +1 other reference |
Quick NavTopAbout OkruschiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Fuchs Quarry, Hartkoppe, Sailauf, Aschaffenburg District, Lower Franconia, Bavaria, Germany